Yesterday's unveiling of what may be the only portrait of Shakespeare painted in his lifetime coincided with another remarkable event: the authentication of the remains of the first theatre in which his plays were staged. It is a coincidence worthy of one of his own intricate plots. It is astonishing that the most researched author in the history of literature can, 400 years on, still throw up such surprises. The social contexts of the two discoveries could not have been more different. "The Theatre", the first purpose-built one in Britain, is located just off Curtain Road, Shoreditch, then a rough area close to where Ben Jonson killed an actor in a duel. Timbers from the Theatre were taken across the Thames to the equally rough Bankside, and used in the construction of the Globe. The painting, by contrast, known until now as the Cobbe portrait, reflected the courtly environment in which many of Shakespeare's plays were staged. It was commissioned by the Earl of Southampton, Shakespeare's patron, to whom he dedicated two of his more erotic poems. Professor Stanley Wells, a Shakespeare scholar, said he had been sceptical but was now 90% certain of its authenticity. Shakespeare left tantalisingly few clues behind about his personal life, not least in the city in which he plied his trade. London needs to rediscover the footprints left by its most illustrious playwright, whose other theatres, Blackfriars and the Curtain, close to the Theatre, still lie unrecognised and unknown to most Londoners.